Lifting systems, within the meaning of the present invention, are used to align transportation system structures in assembly stations with respect to height. The term “transportation system structure” is to be understood as a transportation system, in other words an escalator or moving walk, in an unfinished state during its at-factory manufacturing assembly or a complete assembly, which can be for example, a frame or truss that during manufacturing assembly is fitted with further elements and/or subassemblies or parts.
During manufacturing assembly it can be important for the transportation system structure to be precisely horizontalized or perfectly accurately level.
A lifting system that is usable for height adjustment of the transportation system structure during its manufacturing assembly can, for example, be embodied in such manner as to have several feet, each of which is cradled in a foot-cradle. Each foot rests for support on a supporting surface. To adjust the height, the supporting surface is raised or lowered.
The main problems and concerns of a lifting system include the following:
Firstly, the lifting system must ensure the most perfect possible horizontalization or height adjustment in the range of a few millimeters or centimeters.
Secondly, the transportation system structures are so bulky and heavy that high mechanical demands must be made on the lifting system.
Thirdly, the lifting systems should be rapidly loadable and quick and easy to operate. The at-factory manufacturing assembly of transportation systems can be greatly rationalized if it takes place in an assembly line. Such an assembly line comprises several assembly stations that are passed through in succession by the transportation system structures and loaded at the same time. In each assembly station, during an assembly phase, station-specific assembly steps are executed. On completion of the as-synchronously-as-possible executed assembly phase, during a transport phase the transportation system structures are taken to the respective following assembly stations, and under optimal fabrication conditions the transport of all transportation system structures should also take place as synchronously as possible. It is self-evident that rapid loading and operation of the lifting systems greatly shortens the manipulation times.
Fourthly, the lifting systems should be inexpensive, since a plurality of them, namely several lifting systems for each assembly station, is required.
Although from U.S. Pat. No. 3,724,015 an adjustable stair in the form of a gangway for use at airports is known, it does not relate to a stair in the context of manufacturing assembly. In addition, the required accuracies are significantly less than are required for the manufacturing assembly of transportation systems.
A lifting system with which the aforesaid problems can be solved has heretofore not been known.
Objectives of the invention are therefore to                create a lifting system that is suitable for use in the manufacturing assembly of transportation system structures;        propose a transportation system cradle with such a lifting system;        propose an intermediate product that consists of such a transportation system cradle and a transportation system structure;        propose an assembly plant for manufacturing assembly onto such an intermediate product or of the transportation system structure of the intermediate product respectively; and        propose a method of executing such a manufacturing assembly.        